Rubber Bellow Seals

How to measure for a mechanical seal:

Measure the pump's motor shaft - this is much more accurate than measuring the old seal itself - select the closest size from the filter options

Measure the diameter of the seat housing in the pump, or the actual seal if this is not possible - select the closest size from the filter options

If you still have multiple options, compare the compressed working length dimensions with the original (inclding the seat). The compressed working length is the length of the seal when it is installed - usually compressed about half way.

ClearShaft DiameterTo find the right inner diameter, measure the pump's motor shaft - this is much more accurate than measuring the old seal itselfi

12mm (8)

14mm (8)

16mm (13)

18mm (10)

20mm (10)

22mm (9)

24mm (11)

25mm (11)

28mm (9)

30mm (10)

32mm (10)

33mm (6)

35mm (9)

38mm (13)

40mm (11)

1 5/8" (1)

43mm (8)

1 3/4" (1)

45mm (7)

48mm (4)

50mm (9)

53mm (2)

55mm (4)

60mm (3)

70mm (1)

75mm (1)

ClearSeat Diameter (mm)This matches the outer diameter of the seal, but it is best to measure the seal's seat for an accurate measurementi

23mm (8)

25mm (8)

27mm (13)

33mm (10)

35mm (10)

37mm (9)

39mm (11)

40mm (11)

43mm (9)

45mm (10)

48mm (16)

50mm (9)

56mm (13)

58mm (11)

61mm (8)

63mm (7)

66mm (4)

70mm (9)

73mm (2)

75mm (4)

80mm (3)

92mm (1)

97mm (1)

ClearCompressed Working Length (mm)This is the overall length of the seal when it is installed - the spring is usually half compressed.i

21mm (7)

26mm (9)

32mm (1)

32.5mm (3)

33mm (3)

34mm (1)

35mm (9)

37.5mm (12)

38mm (5)

40mm (23)

42.5mm (24)

45mm (34)

47.5mm (11)

50mm (14)

52.5mm (2)

55mm (16)

60mm (12)

70mm (1)

ClearRotary Face Material

Silicon Carbide (Silver/grey, very hard) (79)

Standard Carbon (Black) (110)

ClearStationary Face Material

Stainless Steel (1)

Ceramic (white) (60)

Silicon Carbide (Silver/grey, very hard) (128)

ClearElastomer Material

Viton (For chemicals, petroleum etc) (52)

Nitrile (For cold water, oils, kerosene, diesel etc up to 80°C) (21)

EPDM (For hot water 80-120°C, some chemicals) (116)

About Dutypoint Direct

Backed up by 40 years of industry experience, Dutypoint aims to offer you helpful advice whether you know nothing, a little or loads about pumps. Our trained advisors are ready to help you purchase the right product first time, every time.

Dutypoint Direct is a trading name of Dutypoint Ltd, a company registered in England and Wales No 09045694